First and foremost let me tell you this, it is okay to feel how you are feeling. It is a tough thing to accept that a person you thought you knew for so long had this part of themselves they had been hiding. In a very real sense, when someone comes out of the closet, those around them grieve them and do in fact go through the stages of grief.

Let's look at your reaction:
"she had never practiced this behavior" - Denial

"I was disgusted" - Anger

"I am seriously hoping and praying that this is just a phase" - Bargaining

"I don't want this to tear us apart" - Depression

The fifth stage of grief is acceptance, but like you said, you are not okay with this. And that is okay. It takes time. You are entitled to your emotions.

But you will get there if you want to. The best tool for that is empathy. Try and see the world from your sister's eyes.

Perhaps my story can help you see that displaying behavior and actually being something are very different.

I am a gay man.

I have always been a gay man.

I was always a little different. A bit more sensitive to things, a bit introspective for a kid. When my friends started to discover girls, I just didn't see the appeal. I knew that's what I was supposed to like so I figured I was just behind. In high school, I not only didn't notice girls, I started to notice boys. This terrified me. Guys WERE NOT supposed to think of guys like that. I was mortified, and prayed constantly to have this burden lifted.

I became depressed and unhealthy. I swore I was straight. I tried kissing girls. Even tried dating one. It hurt me to my core that I couldn't enjoy it. Why God, why did you do this to me?

Then I went to college. For the first time, I met people like me. I was floored because not only were they open about liking the same sex, they were happy. They were well adjusted. They had loving, real relationships.

I realized that while God had placed a burden on me, it wasn't to turn away from how He made me, it was to accept it and learn to love myself. He'd been answering my prayers all along, I just wasn't listening.

Soon after, I came out to my parents. They thought they did something wrong. They thought they did this to me. They thought it was a phase. The thing that terrified them the most was how much I changed. Before I came out, I would go to work, help out around the house, see friends, and joke around with them. But after I came out I would go to work, help out around the house, see friends, and joke around with them. The thing that changed wasn't me; it was them. I was the same person I'd always been, but now they knew that person was gay.

From a purely logical and scientific standpoint, being gay is not a phase or a choice. I "chose" not to be gay for over ten years and it lead to a very dark time in my life. Your sister "chose" not to be gay and as you put it, created "a negative environment from her past relationship with [her husband]". Yes, I'm sure she adores her kids, but choosing to deny who she was clearly was hurting her. As for the science, every major medical and psychological board agrees; homosexuality is both natural and innate. Being gay is normal. The hard thing to wrap one's head around is that your "normal" may not be everyone else's "normal".

So your sister has found someone she loves completely and honestly. Good for her. I did too. My parents have come a long way. They were once homophobic and scared of the new people I'd have in my life. Now they treat me with all the love they used to, and extend that love to my boyfriend of 4 years. His photo is up on the wall with all the rest of the family in their house. Perhaps one day you'll get there too.

You don't have to get there today. What you can do is start making progress. You've always been close with your sister, so talk to her. It will be uncomfortable and it might even bring a few tears, but you will be the better for it. You are disgusted with your sister, and I'm sure it's in part due to the fact that you know in your heart of hearts, that a woman cannot love another woman like she could a man. You know what? In my heart of hearts I know a man cannot love a woman like he would another man. The simple truth is that we are wired differently on a fundamental level. That is to say, you don't have to "get" how your sister's love works, you just have to accept that it's hers and it's real.

Give yourself some slack, it's a tough transition. Perhaps your new sister in-law is a bit more masculine than you'd expect, but again, just because it is not your "normal" doesn't make it abnormal. You clearly have a lot of love in your heart, so be prepared to keep it flowing. Your sister didn't come out to hurt you, or hurt herself. She came out to heal herself. Your sister made the conscious decision that she felt she was worth it as a person to fight for her happiness. What a wonderful lesson to teach her kids.

It will be a journey for the both of you. Try and be open minded. Try to be honest. Ask for help when you are unsure, confused or scared. With a little education and time, my family became my biggest allies and support to me. It may not happen overnight, but you can get there too.

All the best,
Steve

I know how you feel, but if you're close with your sister and don't want something to tear you two apart , you need to talk with her. It may help you if you two talk about it. Yes it's hard to accept, but she can't help the way she feels about women the way you feel about your interests. You really have to try so hard and this will be a great test for that.

Quick questions:
-Why in the heck are you so obsessed with who your sister sleeps with?
-Are you truly so ignorant as to think she is not the same person?
-Who died and left you in charge of everyone's sexuality?
-----Are you the sex police?
-----Do they give for a badge for that?
-----Is it plastic with a little cross in the center perchance?
-What's so special about you that you get to judge your sister?
-Is this a crazy christian thing? Cause if it is, I'll just stop trying to get you to see how truly absurd your post is.